In recent years, the poultry industry has been booming in countries around the world including Japan, Europe, Southeast Asia, America, North America, and South America. In each country, contagious diseases such as the avian influenza are legally designated contagious diseases and prevention of virus propagation is managed by the country. On the other hand, for management of a breeding environment of livestock, in order to limit entry of virus into a poultry house, by introducing a closed poultry house (such as a windowless poultry house) or the like, a substantially completely isolated environment can be created. However, the current situation is that it depends on business efforts of a business owner.
Further, in recent years, due to the revision of animal protection laws, business owners are obligated to improve and maintain appropriate breeding environments and technology, and the burden on the owner has thus been increasing. At the same time, among those pests that increase with deterioration in the breeding environment, chicken mites, in particular, cause direct damage to poultry production, and the impact of this damage is becoming globally evident.
Currently, however, certain points concerning the relation between the increase of chicken mites and the quality of the breeding environment are still unclear, and the timing of extermination and an effective extermination method have not been determined.
Sustained hot and humid conditions in the living environment of chicken mites, such as those which occur during the rainy season, result in prolific chicken mite reproduction. Closed poultry houses, in particular, have problems with prolific reproduction of chicken mites measuring about 0.5-1.0 mm in length. Chicken mites prefer narrow places, such as spaces between parts (for example, the hinges of metal parts forming a chicken cage), and they form nests (colonies) in such places. They crawl out of these spaces to parasitize the chickens and suck their blood. This blood sucking by chicken mites causes such problems as a reduction in the egg collection rate and reduced egg quality in the chickens affected. Therefore, eliminating the damage caused by chicken mites is extremely important in the business operations of poultry farms.
As described above, for the business owner, not only do such infestations cause a reduction in the productivity of poultry farming, but, in addition, despite the considerable cost and effort involved in extermination, there is currently no tool for investigating chicken mites.
Therefore, development of a tool that can serve as an indicator for exterminating chicken mites will not only contribute to improved productivity for poultry farmers but will also lead to improvement of the breeding environment. Therefore, extermination of chicken mites is important to poultry farmers.
Chicken mites not only damage chickens in the poultry house, but can also adhere to and suck the blood of workers working in the poultry house. In such cases, the workers may develop long-term dermatitis or itchy skin and may also experience allergic symptoms. Therefore, extermination of chicken mites not only improves the breeding environment, but also leads to improvement in the working environment for the worker.
Conventionally, extermination of chicken mites is usually performed by spraying a chemical such as a pesticide. However, such a chemical may contain substances that are also toxic to humans and chickens, and there will be restrictions governing its use. For this reason, when spraying such a chemical in a poultry house, it is necessary to move the chickens to a different place. However, such movement causes stress for the chickens, and this stress can result in the additional problem of a reduced egg collection rate.
Further, the chemical sprayed will not penetrate narrow spaces, such as the hinges in the cages that house chickens in the poultry house. Therefore, chicken mites that hide in such spaces cannot be exterminated. In addition, when a chemical is sprayed multiple times, some chicken mites may become resistant to the chemical, and when these chicken mites propagate, the usual chemical will no longer be effective.
In recent years, a technology has been developed in which pests are captured by using electricity and without using a chemical. Specifically, the technology has been developed in which electrostatic induction produced by an electric field is used to physically capture pests and the like (for example, Patent Documents 1-3). In such technology, due to the electric field generated by the application of high voltage to a pair of separated electrodes, electrostatic induction occurs in the pest when it approaches the electrodes, and the pest adsorbs to the electrodes. That is, the technology uses the principle of electrostatic adsorption. The principle of electrostatic adsorption is as follows.
First, when a high voltage is applied to a pair of electrodes, a potential difference is formed between them, generating an electric field. When a pest or the like enters the electric field, the field causes electrostatic induction to occur in the pest or the like. That is, due to electrostatic induction, a charge imbalance occurs on the body surface of the pest or the like. Then, due to the Coulomb force generated between the charge imbalance that occurs on the pest's body surface and the electrode, the pest or the like is adsorbed to the electrode and thereby captured. Such technology has the advantages that no chemicals are used and that small pests, such as aphids and mites, that are difficult to capture using an insect screen, can also be captured. It is conceivable that such technology is also applicable to capturing chicken mites in a poultry house.
In addition, a technology has also been developed in which pests and the like are attracted to a specific place by emitting a pheromone, light (such as ultraviolet light) or a color of light favored by pests and the like (for example, Patent Document 4).